Centrifugal friction clutch



Sept. 15, 1931. K. .1. wERsALL CENTRIFUGAL FRICTION LuTcH Original Filed April 23, 1927 Patented Sept. 15, 1931 UNITED STATES PATENT OFFICE.

KARL JOHAN WERSALL, 0F STAMFORD, CONNECTICUT, ASSIGNOR TO AMERIUAN KAMBI COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE CENTRIFUGAL rnrc'rrolv CLUTCH Original application filed April 23, 1927, Serial No. 185,962, and in Germany January 13, 1927. Divided and this application filed May 4, 1929.

This invention relates to centrifugal friction clutches in which the centrifugal friction bodies or shoes are actuated through the medium of a driver, and is a division of my pending application, Serial No. 185,962, filed April 23, 1927. To increase the wearing resistance of the clutch, it is very important that the maximal unit pressure in the friction surface should be reduced to the minimum. In all known prior constructions of clutches, the surface pressure is considerably greater at one end of the shoe,generally at the front end of the same,on account of the turning moment resulting from the driving power and the friction power tending to press the front end of the shoe with greater pressure against the track than the rear end.

According to the present invention, the required pressure distribution is obtained by insuring a turning moment of the shoe in the opposite direction, tending to lighten the pressure of the shoe at the front end. The result is obtained, in the present improvement, by constructing the contact surface between the driver and the friction shoe so that the generator of this surface in a plane at right angles to the shaft forms an acute angle with the tangent to the track surface at the point of intersection of said generator with said track surface, the point of said acute angle being directed in the direction of rotation of the clutch. With this construction the cen trifugal force will act less on the foremost or leading part of the centrifugal friction body or shoe than on the rear or trailing part, since a component of the centrifugal force acting on the said body will be taken up by the inclined contact surface of the driver instead of being allowed to act radially and directly on the track surface of the clutch, as in prior known constructions. The generator of the contact surface between thedriver and the centrifugal friction body may advantageously form an angle of from five to thirty degrees (530), with the radius through the Serial No. 360,504.

outermost point of contact between the said body and the driver taken in a plane at right angles to the shaft.

In the drawings accompanying and forming a part of this specification Figure 1 is a sectional view through a clutch at right angles to the shaft, with the contact surfaces of the driver and centrifugal friction body or shoe formed according to the present invention;

Fig. 2 is a side view showing the centrifugal friction body with the contact surface of the driver placed at the front end thereof;

Fig. 3 shows an arrangement of a driver axially placed in the centrifugal friction body, the driver pin being fastened to the driver; I

Fig. 4 is a cross-sectional view of the arrangement shown in Fig. 3;

Fig. 5 is a view similar to Fig. 3 illustrating a modified arrangement wherein the driver pin is fastened to the centrifugal friction body; and

Fig. 6 is a cross-sectional view of the ar-v rangement shown in Fig. 5.

Similar characters of reference indicate corresponding parts in the several'views.

Before explaining in detail the present improvement and'mode of operation thereof, I desire to have it understood that the invention is not limited to the details of construction and arrangement of parts which are illustrated in the accompanying drawings, since the invention is capable of otherembodiments, and that the phraseology which I employ is for the not of limitation.

The driver D carried by a suitable shaft, in Fig. 1, is of frusto-conical form-and,

therefore, wedge-shaped-with the smaller end of the wedge toward the center. 271 represents the plane of contact between the driver D and the centrifugal friction body or shoe B, the point 2 being the point of intersection of this plane with the friction sur- I ets'of the driver.

face of the track A. 2-3 is an imaginary radial line drawn from the point 2, and 56 represents the tangent to the friction surface of A at the point 2, while 4E73 is the radius drawn through the outermost contact point 7 between the driver D and the centrifugal body B. It will be observed that the angle 126 is an acute angle. When the driver D is rotated in the direction of the arrow an, the leading end of the centrifugal body will be drawn somewhat towards the ce'iiter of the clutch on account of the angle 126, the point ofwhichis directed in the direction of rotation, being less than a right angle.

The generator andsurface of contact form with the radius 473 an angle l- 73 of five to thirty degrees (530). Should a looseor protruding particle be present on the friction track and the centrifugal body or shoe slide onto it, said centrifugal. body can position itself relatively to the track much more easily and glide over such particle when the foremost end of the body presses more lightly against the track than does the rear end thereof, and thetra'ck will wear much better than is the case with known constructions in which no provision is made for reducing the frictional contact pressure at the leading end of the centrifugal body or shoe.

In Fig. 2 the contact surface of the driver is placed at the front end of the centrifugal body or shoe against the stirrup C, with the contact surfaces lying on lines 2 "l The line 5 6 is the tangent to the track at the point 2 and the angle l 2 6 is acute,angle 7 3 being chosen, as hereinb'efore stated, in order to prevent undue wear on the friction surfaces of the track A and the centrifugal body B.

In Figs. 3 and 4, with the driver pin D" fastened to the driver '1), the angle 1"7"3" must be maintained within the above inentioned limits of 5 30,-the angle 1"2"6", therefore, be'ingalso an acute angle.

In Figs. 5 and 6 the driver pin D is,- as in Figs. 3 and 4-, afiially arranged, but is fixed oh the centrifugal body. When the movement of the centrifugal bodies'is to the right, as in the direction of the arrow g), the angle "2"%3 must be made 5 30",'or, in other words; the angle l"*2' 5, which the plane of driving contactinakes with the tangent 5'6" to the track at the point 2 in a plane at right angles tothe shaft, is acute and also hasits point directed in the directien of the movement of the clutch.

It will be observed that in the present eon: striictions the driver has contact with the shoe intermediate the front and rear endsof the shoe and consequently the shoe 1s not driven from the rear nor is it located in pock "Having now particularly described and as certained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is 2- 1. In a centrifugal friction clutch, the combination of a driven trackmember, a shaftcarried driver, and a shoe, the driver having contact with the shoe intermediate the front and rear ends of the shoe, the plane of the contact surface between the shoe and driver being so located with the tangent to the track that at the intersecting point thereof itforms an acute angle pointing in the direction of rotation.

2. Ina centrifugal'frictionclutch, the com bination of a driven track member, a shaftcarried driver,and a shoe, the driver having contact with the shoe intermediate the front and rear-ends of the s hoe,-the plane of the contact surface between the shoe and driver being so located with the tangent to the track that at the intersecting point thereof it forms an acute angle pointing in the direction of i rotation, such plane of'contact also forming I with a radial line from the shaft intersecting such intersecting point an acute angle.

3. In a centrifugal friction clutch, the combination of a driven track" member, a shaftcarried driver, and a friction shoe, the driver having contact with the shoe intermediate the front and rear ends of the shoe, said shoeand driver having a surface therebetween arranged so that the generator of the contact surface between the driver and the friction shoe in a plane atright angles to the shaft forms an angle less than a right angle with the tangent to the track at the point of intersection of the generator with the same, the angle pointing in the direction of rotation.

4a. In ac'eiitrifugal friction clutch,--the com bination of a driven track member. a shaftcarried driver, and a friction shoe,the driver having contact with the shoe intermediate the front and rear ends of the shoe, said shoe and driver having a frusto conical surface therebetween arranged so that'the generator of the contact surface-between the driver and'the friction shoe in a plane at rightang'les to the shaft forms an acute angle with the'tangent t6 the track at the point of intersection of the generaor with the same,- the angle pointing in the direction of rotation.

5. In a centrifugal friction clutch, the com bination of a driven track member, a'shaftcarried driver, and'a'friction shoe, the driver having contact with the shoe intermediate the front and rear ends of the shoe, said shoe 7 and driver having a surface therebetween' arranged so that the generator of the contact surface. between the driver and the friction' shoe in a plane at right angles to the shaft forms an acute angle with the tangent to the track' at the point of intersection of the generator with the same, the angle pointing in the direction of rotation and the plane of such contact sur'face'also forming with a radial line from the shaft intersecting such interseating point an acute angle.

6. In a centrifugal friction clutch, the combination of a driven track member, a shaftcarried driver, and a shoe, the driver having contact with the shoe intermediate the front and rear ends of the shoe, said shoe and driver having a contact surface in a plane at right angles to the shaft forming an acute angle with the tangent to the track at the point of intersection of the plane of said contact surface with the track, with the angle pointing in the direction of rotation of the shoe, the plane of such contact surface forming with a radial line from the shaft and intersecting such point of intersection an acute angle.

7. In a centrifugal friction clutch, the combination of a driven track member, a shaftcarried driver, and a shoe, said shoe and driver having a contact surface in a plane at right angles to the shaft forming an acute angle with the tangent to the track at the point of intersection of the plane of said contact surface with the track, with the angle pointing in the direction of rotation of the shoe, the plane of such contact surface forming with a radial line from the shaft and intersecting such point of intersection an angle of from five to thirty degrees.

8. In a centrifugal friction clutch, the combination of a driven track member, a shaftcarried driver comprising a radially-located conically-shaped pin, and a shoe, said shoe and driver having a contact surface in a plane at right angles to the shaft forming an acute angle with the tangent to the track at the point of intersection of the plane of said contact surface with the track, with the angle pointing in the direction of rotation of the shoe, the plane of such contact surface forming with a radial line from the shaft and intersecting such point of intersection an angle of from five to thirty degrees.

Signed at Room 1822, 15 Park Row, New York, N. Y., this 3rd day of May, 1929.

KARL J OHAN WERSALL. 

